Azo compounds and process for coloring therewith



Patented Dec. 20, 1938 UNITED STATES PATENT OFFICE AZO COMROUNDS'AND rnoonss FOR COLORING 'rnannwrrn Jersey No Drawing. Application January 23, 1937,

Serial No.122,078

11 Claims.

This invention relates to aromatic azo compounds. More particularly, it relates to nuclear non-sulfonated aromatic azo compounds suitable for the coloration of organic derivatives of cellu- 5. lose. The invention includes the azo compounds, the process for their preparation, the process of coloring with them and materials colored with the azo compounds of the invention.

Organic derivatives of cellulose are character- 10 ized by an indifierent affinity for the usual cotton or wool dyes, especially the ordinary water-soluble dyes. Typical organic derivatives of cellulose include the hydrolyzed as well as the unhydrolyzed cellulose organic acid esters, such as cellu- 15 lose acetate, cellulose formate, cellulose propionate or cellulose butyrate, and the hydrolyzed as well as the unhydrolyzed mixed organic acid esters of cellulose, such as cellulose acetate-propionate, cellulose acetate-butyrate, and the cellulose 20 ethers, such as methyl cellulose, ethyl cellulose or benzyl cellulose.

We have discovered that a valuable series of aromatic azo compounds can be obtained by coupling aromatic diazonium salts in an alkaline 25 medium with compoundsof the type represented by the formula:

30 A N R: I

wherein X represents oxygen or sulfur, R represents hydrogen, an alkyl group, an alkaryl group, or an aryl group and R1 represents an alkyl, an alkaryl or anaryl group. The alkyl and aryl sub 5 stituents may be substituted or unsubstituted as will be apparent from the description hereinafter.

The compounds of our invention have the probable formula:

wherein X, R and R1 have the meaning above taining organic derivatives of cellulose. The dye ings produced employing said non-sulfonated azo compounds are, in general, Jf good fastness to light and washing and range in shade from 'greenish yellow to red. The nuclear sulfonated compounds of the invention possess less or no utility 5 for coloring organic derivatives of cellulose but may be employed for coloring cotton, natural silk or wool by customary methods of application.

Referring more particularly to the nuclear nonsulfonated aryl compounds of our invention, we 10 have found that when X is oxygen, compounds having improved lightfastness on organic derivatives of cellulose are obtained when the aryl nucleus contains a substituted or unsubstituted alkoxy or aryloxy group in the ortho position to 18 the azo linkage. When X is sulfur, we have found that compounds having markedly increased light fastness on organic derivatives of cellulose, particularly cellulose acetate silk, are obtained when there is 2. nitro group on the aryl nucleus in ortho 20 position to the azo linkage. Further, we have folmd that when R and R1 are alkyl groups, the affinity of the compounds for organic derivatives of cellulose is improved if R and R1 are difierent alk l groups.

The following examples illustrate the preparation of the compounds of our invention:

Eximrmi' 1 9.3 grams of aniline are dissolved in 50 cc. of water containing 25 cc. of 86% hydrochloric acid. The resulting solution is cooled to a temperature approximating 0-5 C. by the addition of ice, for example, and diazotized by adding, with stirring, 6.9 grams of sodium nitrite dissolved in water.

14.2 grams of l-methyl barbituric acid are dissolved in 100 cc. of water containing 10 grams of sodium hydroxide. The resulting solution is iced and the diazo solution prepared above is added with stirring. When coupling is complete the mixture is made acid to litmus with acetic acid or a mineral acid such as hydrochloric acid and the desired azo compound is recovered by filtration, washed with water, and dried.

The corresponding thiobarbituric acid compound may be obtained by the substitution of 15.8 grams of l-methyl thiobarbituric acid or the l-methyl barbituric acid of the example.

Emma 2 12.1 grams of o-anisidine are dissolved in water containing a suitable acid such as hydrochloric acid and diazotized in the usual manner by the addition of 6.9 grams of sodium nitrite dissolved in water. I

15.6 grams of 1,3-dimethyl barbituric acid are dissolved in 200 cc. of water containing 21 grams of sodium carbonate. The resulting solution is cooled and the diazo solution prepared above is added, with stirring. Upon completion of the coupling reaction the mixture is made acid to litmus with hydrochloric acid and the dye com-.

pound formedis recovered by filtration, washed with water, and dried.

If 17.2 grams of 1,3-dimethyl thiobarbituric acid are substituted for the 1,3.-dimethyl barbituric ac d of the example, the corresponding thiobarbituric acid derivative will be obtained.

EXAMPLE 3 13.7 grams of o-phenetidine are dissolved in 200 cc. of water containing about 36 grams of 36% hydrochloric acid. The resulting solution is cooled to a temperature approximating -5! C. and diazotized by the addition, with stirring, of 6.9 grams of sodium nitrite dissolved in water.

17 grams of l-methyl-3-ethyl barbituric acid are dissolved in 150 cc. of water containing 10 grams of sodium hydroxide. The solution thus formed is cooled and the diazo solution prepared above is added, with stirring. When coupling is complete the mixture is made acid to litmus with hydrochloric acid and the dye compound formed is removed by filtration and subjected to the usual washing and drying operations.

By the substitution of 18.6 grams of l-methyl- 3-ethyl thiobarbituric acid for the 1-methyl-3- ethyl barbituric acid of the example the corresponding thiobarbituric acid compound may be prepared.

EXAMPLE 4 15.3 grams of p-hydroxy-o-phenetidine are diazotized in the usualmanner and coupled with 20.4 grams of l-phenyl barbituric acid dissolved in 200 cc. of water containing 21 grams of sodium carbonate. Coupling and recovery of the desired azo compound may be carried out as previously described.

The corresponding thiobarbituric acid derivative may be obtained by the substitution of 22 grams of l-phenyl thiobarbituric acid for the 1- phenyl barbituric acid of the example.

EXAMPLE 5 16.7 grams of fl-methoxy-o-phenetidine are diazotized in the usual manner and coupled with 27.8 grams of 1-p-methoxy-phenyl-3-p hydroxyethyl barbituric acid dissolved in 250 cc. of water containing grams of sodium hydroxide. Coupling and recovery of the dye compound formed may be carried out as previously described.

By the substitution of 29.4 grams of l-p-methoxy-phenyl-3-p-hydroxyethyl thiobarbituric acid for 1-p-methoxy-phenyl-3-p-hydroxyethyl barbituric acid of the example the corresponding thiobarbituric acid derivative may be prepared.

EXAMPLE 6 16.5 grams of 3-methoxy-4-aminophenylmethylketone are diazotized in the usual manner.

22.5 grams of l-benzyl barbituric acid are dissolved in a dilute aqueous solution of sodium hydroxide. The resulting solution is'cooled and the diazo solution prepared above is added. with stirring. When coupling is complete the mixture is made acid to litmus with acetic or hydrochloric acid, for example, and the desired azo compound is recovered by filtration, washed with water, and dried.

The corresponding thiobarbituric acid conipound may be prepared by substituting 24.1 grams of l-benzyl thiobarbituric acid for the l-benzyl barbituric acid of the example.

' EXAMPLE 7 13.8 grams of o-nitroaniline are added to 200 cc. of water containing 40 cc. of 36% hydrochloric acid. The resulting mixture is cooled and the amine is diazotized by the addition of 6.9 grams ofv sodium nitrite dissolved in water.

17.2 grams of l-ethyl thiobarbituric acid are dissolved in 200 cc. of water containing 22 grams of sodium hydroxide. The resulting solution is iced and the diazo solution prepared above is slowly added, with stirring. When coupling is complete the mixture is made acid to litmus with hydrochloric acid and the dye compound formed is removed by filtration, washed with Water, and dried.

By the substitution of 15.6 grams of l-ethyl barbituric acid for the l-ethyl thiobarbituric acid of the example the corresponding barbituric acid derivative may be prepared.

ExAMrLE 8 may be prepared by substituting 1,3-dimethyl barbituric acid for the 1,3-dimethyl thiobarbituric acid of the example.

EXAMPLE 9 15.4 grams of o-nitro-p-methylaniline are diazotized according to the method described in Example 7.

26.2 grams of 1-benzyl-3-p-hydroxyethyl thiobarbituric acid are dissolved in a dilute aqueous sodium hydroxide solution. The solution formed is cooled and the diazo solution prepared above is slowly added, with stirring. Upon completion of the coupling reaction the mixture is made acid to litmus with hydrochloric acid and the precipitated dye compound is removed by filtration, I

washed with water, and dried. I

The corresponding barbituric acid compound may be prepared by substituting 24.6 grams of 1-benzyl-3-fi-hydroxyethyl barbituric acid for the l-benzyl-3-fi-hydroxyethyl thiobarbituric acid of the example. EXAMPLE 10 29.5 grams of are diazotized according to the method described in Example 7 and coupled with 18.6 grams of 1-methyl-3-ethyl thiobarbituric acid dissolved in 200 cc. of water containing 40 grams of sodium carbonate. Coupling and recovery of the dye compound may be carried out as previously described. I

EXAMPLE 11 (A) 7.6 grams of sodium nitrite are dissolved in 53 cc. of concentrated sulphuric acid (sp. gr. 1.83). After the addition the solution is warmed to a temperature not exceeding 70 C; and then cooled to 10-15 C.

(B) 18.3 grams of 2,4-dinitroaniline are dissolved in 225 cc. of hot glacial acetic acid and then cooled rapidly to room temperature.

Solution A is stirred and mixture B is added thereto over a period of one hour while maintaining a temperature of 1015 C. After the addition the resulting solution is stirred for 30 minutes, 1 gram of urea being added to remove any excess nitrous acid.

23.2 grams of 1,3-di-fi-hydroxyethyl thiobarbituric acid are dissolved in an aqueous solution of sodium hydroxide containing a large excess of the alkali. The resulting solution is cooled and the diazo solution prepared as described above is slowly added, with stirring. Coupling and recovery of the reaction product may be carried out as described in the previous examples.

Inorder that our invention may be fully understood, the preparation of a number of substances used in the manufacture of the compounds of our invention is disclosed hereinafter.

I-methyl barbituric acid This compound may be prepared as described in Berichte der Deutschen Chemischen Gesellschaft, volume 54, page 1037. (1921).

By substitution of other alkyl ureas for methyl urea other alkyl barbituric acids can be prepared in accordance with the method described for the preparation of l-methyl barbituric acid.

l-ethyl barbituric acid This compound may be prepared as described in Berichte der, Deutschen Chemischen Gesellschaft, volume 54, page 1038 (1921).

1,3-diethyl barbituric acid This compound may be prepared as described in Berichte der Deutschen Chemischen Gesell schaft; volume 54, pages 1038-9 (1921).

1-methyl-3-ethyl-barbituric acid 102' grams of methyl ethyl urea are dissolved in' 500 cc. of absolute ethanol and added to a solution of 23 gm. of sodium in 500 cc. of boiling absolute ethanol containing 160 grams'of ethyl malonate. The resulting mixture is refluxed for 7-10 hours and hydrochloric acid (sp. gr. 1.18) is then added until the mixture is slightly acid to Congo red paper. 1000 cc. of water are added. On standing, l-methyl-S-ethyl barbituric acid crystallizes out.

l-p-hydroxyethyl barbituric acid 110 grams of p-hydroxyethyl urea are dissolved in 500 cc. of absolute ethanol and added to a solution of 23 grams of sodium in 500 cc. of absolute ethanol containing 160 grams of ethyl malonate. Twice as much sodium as described may be employed. The resulting mixture is refluxed for 7-10 hours and worked up in the manner described for 1-methyl-3-ethyl barbituric acid.

1-m ethyl- 8-hydroxyethyl barbituric acid and 1,3-di-p-hydroxyethyl barbituric acid may be prepared in an exactly similar manner by the substitution of respectively, for the p-hydroxyethyl barbituric acid of the example.

I-phenyl barbituric acid This compound may be prepared as described on pages 1252 and 1253 of the Journal of the Chemical Society for 1926.

l-bengyl barbituric acid 138, grams of benzyl urea in 500 cc. of absolute ethanol are added to a boiling solution of 23 grams of sodium in 500 cc. of absolute ethanol containing 160 grams of ethyl malonate. The mixture is refluxed for 7-10 hours and hydrochloric acid is then added until the mixture is acid to Congo red paper. 1000 cc. of water are added to the acid mixture. On standing, 1- benzyl barbituric acid separates.

By the substitution of H, N CHrCu Q and canoom listed under the heading Amine and coupling with the compounds specified in the column entitled Coupling Component. The diazotization and coupling reactions may be carried out in accordance with the general procedure disclosed in Examples 1-11, inclusive.

3-nitro-4-aminophenylmethylketone.

m-Phenoxyaniline Tabulation A-Substituted barbituric acid derivatives Amine Coupling component Color on cellulose acetate silk p-Phenetidine o-Anisidine. m-Anisidine p-Toluidine o-Bromoaniline g1) l-methyl barbituric acid 2) 1,3-dimethy1 barbituric acid (3) l-methyl-E-ethyl barbitgu'iq acid m-Bromoaniline p-Bromoani1ine. o-Cbloroaniline. m-Chloroaniline p-Chloroaniline o-Fluoroaniline m-Fluornanilinp p-Fluoroaniline o-Iodoaniline p-Iodoaniliue -w-Hydroxyethoxyamhne m-w-Hydroxyethoxyaniline. p-w-Hydroxyet-hoxyaniline o-Phenoxyaniline p-Phenoxyaniline. l-amino-Z-methoxy-4,5-dxhalobenzene 1-amino-2-ethoxy-4,5-dihalobenzene l-amin0-4-methoxy-5-dihalobenzene l-amino-l-ethoxy-5-diha1obenzene. o-methoxy-p-methylaui]ine" o-Methoxy-p-ethylaniline o-E thoxy-p-methylan i1 i n p o-Ethoxy-p-ethylaniline o-Methyl-p-methoxyaniline. o-Methy1-p-eth0xyaniline o-Eth'yl-p-metboxy o-Ethyl-p-eth'oxyanilinp 1-arnino-2,4-dihalobenzene l-amino-2,5-dihalo PM o-Methyl-p-ethy o-Ethyl-p-methylaniline 1-amino-2,4-dimethylbenzene. 1-amino-2,4-diethylbenzeneo-Nitroaniline m-Nitr0aui1ine p-Nitroaniline o-Nitro-p-haloaniline o-Nitro-p-methoxyaniline o-Nitro-p-ethoxyaniline. o-Methoxy-p-nitroaniline o-Ethoxy-p-nitm o-Methyl-p-nitroanilinn o-Ethyl-pmitrnnnilinp p-Aminoacetophenone 3-methoxy-4-aminophenylmethylketone- 3-ethoxy-4-aminopheny1methylketone. 3-halo-4-aminophenylmethylketone 1-amin0-2,4-dinitrobenzene a-Naphthylamine p-Aminodiethylanidina...

p-Phenylene diamine CHzQCH:

Gteenish-yellow. o.

Red. Orange-red.

Greenish-yellow.

' our invention as dyes, they will ordinarily be ap- Tabulation BSubstituted thiobarbituric acid derivatives Amine Coupling component gggi gg Same amines as (I; l-methylthiobarbituric acid Greenish-orange-yellow. under ,Tabula- (2 1.3-d1metl1yl thiobarbituric acid- Do. tion A-subst1- (3) 1-methy1-3-ethyl thiobarbituric Do. tutedbarbituric acid. a ci d co m (4) l-methyl-3-propylthiobarbituric Do. pounds. aci

-(5) l-methyl-3-phenyltbiobarbituric Do.

ac (6) l-mqthyl-3-benzylthiobarbiturle Do.

sci (7) l-p-cingathoxphenylthiobarbituric Do.

a (8) l-benzyl thiobarbituric acid..." Do. (9) 1.3-diphenyl thiobarbituric acid. Do. (10) 1,3-di-B-bydroxyethyl thiobar- Do. bituric acid.

Where the amine employed is p-aminodiethylaniline and' p-phenylene diamine the colors produced on cellulose acetate silk are red and orange red, respectively.

In the above tabulations reference has been made to halogen substituted amines such as 1-amino-2-methoxy-4, 5-dihalobenzene and 1- amino-2,4-dihalobenzene, for example. These .amines may have the same or different halogen atoms. v

In employing the aromatic azo derivatives of plied to the material in the form of an aqueous suspension which can be prepared by grinding the dye to a paste in the presence 'of a sulfonated oil, soap, or other suitable dispersing agent and dispersing the resulting paste in water. Dyeing operations can, with advantage, be conducted at a temperature of SO-85 C., but any suitable temperature may be used. In accordance with the usual dyeing practice, the material to be dyed will ordinarily be added to the aqueous dye bath at a temperature lower than that at which the main portion of the dyeing is'to be effected, a temperature approximating 45-55 C., for example, following which the temperature of the dye bath will be raised to that selected for carrying out the dyeing operation. The temperature at which the dyeing is conducted will vary somewhat, depending, for example, on the particular material or materials undergoing coloration.

The amount of dispersing agent employed may be varied over wide limits. Amounts approximating 10 to 200% by weight on the dye may be I employed, for example. These amounts are not -to' be taken. as limits as greater or lesser amounts can be used. To illustrate, if the dye is ground to a sufiiciently fine powder dyeing can be satisfactorily carried out without the aid of a dispersing agent. Generally speaking, however, the use of a dispersing agent is desirable.

Advantageously, dyeing is carried out in a substantially neutral dyebath. Perhaps, moreaccurately, it should be stated that dyeing should not be carried out in an alkaline dyebath, that is, one having any substantial alkalinity, since the presence of free alkali appears to afiect the dyeing adversely. Dyeing in an acid dyebath is not recommended because of the tendency of 0 acids to affect the material undergoing dyeing adversely. Because of these considerations when a dispersing agent is to be employed preferably it is neutral or substantially neutral.

It will be understood that the azo compounds of our invention may be applied to the material to be colored in any suitable manner; Coloration may be effected, for example, by dyeing, printing, or stenciling. 'Dispersing or solubilizing agents that can be employed for preparing suspensions of the dye include soap, sulphuricinoleic acid, salts of sulphoricinoleic acid, a water soluble salt of cellulose phthalate, cellulose succinate or cellulose mono-acetate diphthalate, for example, the sodium, potassium or ammonium salts, and sulfonated oleic, stearic or palmitic acid, or salts thereof, such, for example, as the sodium or ammonium salts.

While it is preferred to effect coloration by applying the dye compound from an aqueous dye bath directly to the material to be colored, the azo compounds of our invention may be applied employing the methods applicable to the so-called ice colors. Briefly, in accordance with this method of dyeing, the amine is absorbed and diazotized on the fiber, after which the dye is formed insitu by developing with a coupling component such as l-methylbarbituric acid, 1,3-dimethylbarbituric acid, 1-methyl-3-ethyl barbituric acid, l-phenylbarbituric acid or l-ethylbarbituric acid, for example. Conversely the material undergoing dyeing orcoloration may first be treated to absorb one of said acid coupling components and the dye subsequently formed in situ by coupling -with an aryl diazonium salt.

The following examples illustrate how dyeing may be carried out in accordance with our invention. Quantities are expressed in parts by weight.

are finely ground with a dispersing agent such as soap or oleyl glyceryl sulfate and the resulting paste is dispersed in 1000 parts of water. The dispersion thus prepared is heated to a temperature approximating 45-55 C. and' 100 parts of cellulose acetate silk, in the form of yarn or fabric, for example, are added to the dyebath afterwhich the temperature is gradually raised to 80-85 C. and the silk worked for several hours at this latter temperature. Sodium chloride may be added as desired during the dyeing operation to promote exhaustion of the dyebath. Upon completion of the dyeing operation the cellulose acetate silk is removed, washed with soap, rinsed and dried. The cellulose acetate silk is colored a greenish-yellow shade of excellent fastness to light.

2.5 parts oi CHaCHs are finely ground with a dispersing agent such as soap or oleyl glyceryl sulfate and the resulting paste is dispersed in 1000 parts of water. The dispersion thus prepared is heated to a temperature approximating 4555 C. and 100 parts of cellulose acetate silk, in the form of yarn or fabric, for example, are added to the dyebath after which the temperature is gradually raised to 80-85" C. and the silk worked for several hours at this latter temperature. Sodium chloride may be added as desired during the dyeing operation to promote exhaustion of the dyebath. Upon completion of the dyeing operation the cellulose acetate silk is removed, washed with soap, rinsed and dried. The cellulose acetate silk is colored a greenish-yellow shade of excellent fastness to light.

EXAMPLE C By the substitution of 2.5 parts of O=C l CHI-CH3 amples, or by substitution of both the material being dyed and the dye compounds of the examples.

We claim: A

1. A process of coloring an organic derivative of cellulose which comprises applying thereto a dye selected from the class of nuclear nonsulfonated azo compounds having the general formula:

wherein X represents oxygen or sulfur, R represents hydrogen, an alkyl group, an alkaryl group or an aryl group, R1 represents an alkyl, an alkaryl or an aryl group and R2 represents an aryl nucleus.

2. A process of coloring an organid'acid ester of cellulose which comprises applying thereto a dye selected from the ,class of nuclear non- -R2 represents an aryl nucleus of wherein X represents oxygen or sulfur, R represents hydrogen, an alkyl group, an. alkaryl group or an aryl group, R1 represents an alkyl, an.

alkaryl or an aryl group and R2 represents an aryl nucleus.

3. A process of coloring a cellulose acetatewhich comprises applying thereto a dye selected from the class of nuclear non-sulfonated azo compounds having the general formula:

O=CNR1 wherein X represents oxygen or sulfur, R represents hydrogen, an alkyl group, an alkaryl group or an aryl group, R1 represents an alkyl, an

alkaryl or an aryl group and R2 represents an aryl nucleus.

4. A process of coloring a cellulose acetate which comprises applying thereto a dye selected from the class of nuclear non-sulfonated azo compounds having the general formula:

o= N-R1 wherein X representsoxygen or sulfur, R1 represents an alkyl, an alkaryl or an aryl group and I the benzene series.

5. A process of coloring a cellulose acetate which comprises applying thereto a dye selected from the class of nuclear non-sulfonated azo compounds having the general formula:

wherein X represents oxygen or sulfur, R represents hydrogen, an alkyl group, an alkaryl group or an aryl group, R1 represents an alkyl, an alkaryl or an aryl group and R2 represents an aryl nucleus of the benzene series having an alkoxy or aryloxy group in the'ortho position to the azo group when X is oxygen and a nitro group in said ortho position when X is sulfur.

6. Material made of or containing an organic derivative of cellulose colored with a dye selected from the class of nuclear non-sulfonated azo compounds having the general formula:

wherein X represents oxygen or sulfur, R'represents hydrogen, an alkyl group, an alkaryl group or an aryl group, R1 represents an alkyl, an

alkaryl oran aryl group and R2 represents an aryl nucleus.

7. Material made of or containing an organic acid ester of cellulose colored with a dye selected from the class of nuclear non-sulfonated azo compounds having the general formula:

'sents hydroge'n, an alkyl group, an alkaryl groupor an aryl group, R1 represents an alkyl, an alkaryl or an aryl group and Ra represents an aryl nucleus,

8. A cellulose acetate colored with a dye 'selected from the class of nuclear non-sulfonated azo compounds having the general formula:

wherein X represents oxygen or sulfur, R represents hydrogen, an alkyl group, an alkaryl group or an aryl goup, R1 represents an alkyl, an alkaryl or an aryl group and R2 represents an aryl nucleus.

'9. A- cellulose acetate colored with a dye selected from the class of nuclear non-sulfonat'ed azo compounds having the general formula:

wherein X represents oxygen or sulfur, R1 represents an alkyl, an alkaryl or an aryl group and R: represents an aryl nucleus of the benzene series.

. 10. A cellulose acetate colored with a dye selected from the class of nuclear non-sulfonatd azo compounds having the general formula:

wherein X represents oxygen or sulfur, R, represents hydrogen, an alkyl group, an alkaryl group wherein R represents hydrogen, an alkyl group, an alkaryl group, or an aryl group, R1 represents an alkyl, an alkaryl or an aryl group and R2 rep resents. an aryl nucleus.

' JAMES a. McNALLY. JOSEPH B. mom. 

